Coal stoker smoke eliminator



Feb. 12, 1935. v c NORQUlsT COAL STOKER- SMOKE ELIMINATOR I Filed Jan.7, 1933 Patented a '12, 193s I UNITED STATES COAL STOKER SMOKEELIMINATOB Victor C. Norquist,- Kansas City Mo., assignor ButlerManufacturing Company, Kansas City,

Mo., a corporation of Missouri Application January 7, 1938, Serial No.650,599

' 1 Claim. (01. 110-44) My invention relates to a coal stoker smokeeliminator and more particularly to a device for preventing backsmoking. in coal'stokers. By

,*back smoking I mean the escape of smoke and/or gases through the coalhopper into the space occupied by the stoker. Back smoking is occasionedby a pressure differential existing between the coal hopper and thecombustion pot. It is to be remembered that the-combustion pot is beingfed'air under slight pressure from a 'bl ower causing an increasedpressure in the region of combustion. The smoking gases escape into, thecellar or other place occupied by'the stoker constituting a source ofannoyance and a source of danger inasmuch as there is liable to becarbon monoxide present in the gases.

The prior art shows several methods of eliminating' back smoking. I havefound that none of the prior art devices will efiectively accomplishthis purpose. Those devices which take a suction on the coal hopper failto work. because the coal becomes packed around the region of thesuction pipe. The suction isnecessarily localized and a great deal ofsmoke willescape. The use of an air tight hopper is inconvenient andfurthermore allows the escape of smoke and gases in a body when thehopper lid is opened for filling.

One object of my invention is to provide a devicefor eliminating backsmoking which will preclude the packing of the suction pipe with coal.

Another object of my invention is to provide a device for preventingback smoking which may be readily installed upon existing coal stokersnot provided with such devices.

4 Further objects of my invention will appear from the followingdescription.

In the accompanying drawing which forms part of the instantspecification and which is to be read in conjunction therewith and inwhich like reference numerals arelused to indicate like parts in thevarious views; g

Figure 1 illustrates an elevation partly in section of a coal stokerattached to a house heating furnace and embodying one mode of carryingout my invention.

, Figure 2 is a sectional elevation of the hopper of a coal stokerfitted with my invention.

Figure 3 is-a sectional view taken on,the line 3-3 of Figure 2.

Figure 4 is a detail viewshowing an ejector which may be used to carryout my invention.

Figure 5 is a side elevation of a coal stoker fitted with another modeof carrying out my inventlon.

Figure 6 is a detail view showing a Venturi nozzle capable of .beingused to carry out my invention.

' In general, my invention consists in forming a space free of cdalwhich extends along one side or completely around-the interior of thecoal hopper. I prefer to form this space by means of a downwardlyinclined baffle secured to the side wall or walls of the hopper. Thisdownwardly inclined bafli extends toward the center 10 of the coalhopper and forms a space which for convenience I will term a smoke box.Communicating with this smoke box is a pipe leading to an ejector deviceso that reduced pressure is maintained in the region of the smoke box.For convenience I will term' this reduced pressure suction f smoke outof the smoke box. ,I may discharge the smoke so withdrawn into thefurnace at any desired point or into the draft pipe from the furnace.Alternatively I may discharge the smoke into the air which goes to thecombustion pot.

More particularly referring now to the drawing, afurnace 1 is providedwith a coal stoker which consists generally of a coal hopper 2 which isset to discharge into a coal duct 3. The coal duct 3 leads to acombustion pot 4 and houses a conveyor screw 5 which is driven by anelectric motor 6 through any suitable transmission gear '7. An electricmotor drives a blower fan 8 which Tdischarges into an air d ct 9 whichleads to the combustion pot an discharges air through tuyeres as is wellknown in the art. The interior of the coal hopper 2 is provided with adownwardly inclined inwardly extending baflie 10 as can readily be seenby reference to Figure 3. This baiiie maybe fitted in any suitablemanner.

I prefer to attach it to one side wall of a coal hopper 2. It may extendcompletely around the interior of the coal hopper if desired but I havefound that this is not necessary in operation. The baflie 10 and theside wall of the coal hopper 2 will form a smoke box having its open anddownward. Leading into this smoke box I fit the suction end'11 of anejector 12. This ejector, 5' may be in the form shown inFigure 4 or maybe of the Venturi type as shown in Figure 6. I provide a branch fitting14 to the discharge end of my'blower '8. Connected to this branchfitting is a conduit 15 which leads to the ejector 12 as can readily beseen by reference to Figure 1. The air passing over the ejector nozzle16 will create a suction in the suction pipe 11 which,

as pointed out above, communicates with the smoke box. The reducedpressure will draw the The suction device will draw the smoke out of thesmoke box discharge 'it through conduit 17 as shown in Fig. 1. Thisconduit may be led to any suitable place such as to the smoke pipe 18 orinto any suitable place in the furnace. If desired, the pipe may'be'ledto discharge out doors.

Another mode of creating a suction in the smoke box and eliminatingsmoke is shown in Figure 5. In Figure 5, a duct 20 is secured to an airinlet 21 of the blower in the region of reduced pressure. The pipe 20communicates to an ejector device 12 as before. Air will be drawnthrough air inlet 22 and will pass through pipe 20 to an ejector 12,thence to the opening of the blower 8. Smoke will be withdrawn throughthe smoke box as before and will pass throughpipe 20 through the blowerby which it is discharged through air conduit 9 to the combustion pot,whence it will pass out through the-smoke pipe It is believed that theoperation of my device will be clear from the foregoing description. Itwill be appreciated that my device will carry out the objects of myinvention. The bafiie 10 will prevent the coal in the coal ductfromclogging up the ejector suction opening 11. Smoke pass ing throughthe coal duct 3 will pass through the and described.

' woman sub-combinations are of utility and may be employed withoutreference to other features and sub-combinations. This is contemplatedby and is within the scope of my claim. It is further obvious thatvarious changes may be made in details within the scope of myclaimwithout departing from the spirit of my invention. It is,

therefore, to be understood that my invention is not to be limited tothe specific details shown Having thus described my invention, what Iclaim is:

v A coal stokerincluding a coal hopper, a smoke collecting hoodpositioned within said hopper, a blower, an ejector device having aninducing medium connection and an induced medium connection, means forplacing said induced medium connection in communication with said hoodand means for passing air from the blower through said inducing mediumconnection.

VICTOR c. 'NORQUIST.

